I just drank from the same paper cup with the same straw as my mom that currently has 2 cold sores!? am i at risk? what to do?

Yes, risk: Most cold sores are caused by viruses, and yes, they are contagious and can be passed around. Not much you can do now - the exposure has already taken place. In future, use your own drink, or at very least, your own straw. Don't recommend overscrubbing face or gums - that will just irritate them and make transmission even more likely. Good normal hygiene is best at this point.